Phthalates: Genes, Diet, and Detoxification Pathways

Key Takeaways:
~ Phthalates are a class of compounds used in plastics, fragrances, food packaging, personal care products, and more.
~ They can leach into the environment and our bodies, acting as endocrine disruptors and increasing the risk of reproductive problems, obesity, asthma, ADHD, and even increased mortality from cardiovascular disease.
~ Phthalates are pervasive in our food supply, from packaging to processing equipment. Studies show that almost all of us have phthalates in our bodies.
~ The body metabolizes phthalates quickly, excreting them in urine, sweat, and feces. Understanding the role that your genetic variants play in phthalate detoxification can help you eliminate them more efficiently.

What are phthalates, and are they harmful?

Phthalates are ubiquitous in our modern world, found in everything from plastics to personal care products. But are they safe? This article explores what phthalates are, where they’re found, and the research on potential health risks.

Phthalates (pronounced THAL-eights) are a class of chemicals used as plasticizers to make plastics more flexible and as fixatives in artificial fragrances. The problem lies in the type of compound they are. Because they are not covalently bonded to plastic polymers, phthalates leach from plastic items when exposed to heat or solvents. For example, phthalates can leach from PVC-containing items (plastics, pipes, vinyl flooring, etc.) and become airborne or part of the soil and water.[ref][ref]

Phthalates are classified as endocrine disruptors, and they have been linked to reproductive harm, such as decreased fertility and pregnancy loss. But that is just the start of the story… Numerous studies have found other insidious negative effects from this pervasive environmental compound.[ref][ref][ref]

Let’s dig into the research studies (in humans!) and then look at how the body breaks down and eliminates phthalates.

Where do we find phthalates?

Phthalates are commonly found in:[ref][ref][ref]

• Artificial fragrances (fabric softener, candles, air freshener, body spray)
• Vinyl products (PVC, vinyl tubing, flooring
• Food and food packaging
• Personal care products (shampoo, lotions, cosmetics, hair care products)
• Carpet backing
• Faux leather, such as in furniture
• Flexible coatings on extension cords and appliance cords
• Coating of household goods and in many brands of paints
• Nail polish (inhaled vapors, absorbed through the nails)
• Coatings on pharmaceuticals
• Medical devices
• Printing inks

Toys:
Exposure to phthalates can be more detrimental to infants and children than adults. Several types of phthalates are banned in the U.S. and EU for use in toys and other items, such as teething rings and bottle nipples, that can fit in a child’s mouth.[ref]

Food packaging:
Packaged foods may contain phthalates due to processing or packaging. In addition, prescription and over-the-counter medicines can contain phthalates as excipients.[ref] Phthalates were even added to boxed mac and cheese!

Artificial fragrances:
In 2010, the FDA created a list of products it had tested for phthalates – fragrances topped the list as a major source of phthalates in the products tested. Think about how often we are exposed to odors, such as in lotion, shampoo, laundry detergent, fabric softener, and air fresheners.

Are phthalates really a problem?

You may wonder if this is just another scary “sky is falling” type of hype. So let’s set a few things straight from the start:

• Phthalate exposure will not kill you outright. Toxicity tests dating back to the 1970s used rats as a model, showing that phthalates were not immediately toxic.[ref]
• Research shows that phthalate pollution in the environment could lead to a global decline in amphibians because phthalates affect frog sperm at very, very low levels.[ref] But… we aren’t frogs.

When looking at animal research studies, it is important to know:

• Animal studies using rats and mice are likely not good models for the human metabolism of phthalates. Recent studies suggest that rats do not metabolize phthalates in the same way as humans.[ref]
• Based on mouse studies, the exposure limits for phthalates are set relatively high, at about 100 mg/kg/day for tumor formation. However, high-level exposure isn’t common, so we need to look at what low-level, chronic exposure does in humans.

Lifelong exposure at low levels, in humans:
A study (2021) found that phthalate exposure increases all-cause mortality, in part due to an increase in cardiovascular disease. The study estimated the impact on people aged 55-64 caused >90,000 attributable deaths/year in the U.S.[ref]

A new study estimated that 13.497% or 356,238 cardiovascular deaths globally were attributed to phthalate (DEHP) exposure. The study found geographic disparities of plastic exposure. The plastic-producing sectors of South Asia and the Middle East had the highest increase of cardiovascular deaths (16.807%). [ref]

Let’s look at some recent studies to see why phthalate exposure at low levels is a problem.

Effects of chronic, low-dose phthalate exposure in humans:

Evidence of the effects of low-level, daily exposure to phthalates in humans and animals includes:

1. Phthalates act as endocrine disruptors.[ref]
2. As endocrine disruptors, phthalates may increase the risk of fibroids, obesity, asthma, ADHD, IVF problems, and reproductive problems in men.[ref][ref]
3. Higher exposure to phthalates has been linked to decreased cognition (studies in children).[ref]
4. In women, higher phthalate levels are linked to obesity and metabolic syndrome.[ref]
5. Chronic exposure to phthalates increases allergies.[ref]
6. Phthalate exposure correlates with the size of uterine fibroids – more phthalates, larger fibroids.[ref]
7. Higher prenatal exposure to phthalates is linked to eczema in children.[ref]
8. Higher phthalate exposure in children is strongly associated with subclinical atherosclerosis.[ref]
9. Phthalate metabolite levels are also linked to higher blood pressure profiles in teenagers.[ref]
10. Metabolites are associated with a 200% increased relative risk of asthma in boys.[ref]
11. Ovarian oxidative stress increases in women exposed to higher phthalate levels.[ref][ref]
12. Phthalates have been linked to testicular dysgenesis syndrome.[ref]
13. Higher levels of urinary phthalates are associated with an increased relative risk of gallstones.[ref]

How are we exposed to phthalates?

Phthalate contamination exists throughout the food supply, from packaging to the equipment used to process foods and dairy products to the food itself.

For example, a 2014 Norwegian study found:[ref]

• Phthalates were present in ALL foods and beverages commonly consumed (and BPA was found in 54%).
• Exposure levels were highest in meat and grains. However, average levels were less than the European maximum exposure level limits.

Can eating organic protect you from phthalate exposure from food? Probably not. One study found that phthalate levels in people who ate junk food were the same as those who ate a controlled organic diet with food stored in glass containers instead of plastic.[ref] This is likely due to phthalate contamination throughout food processing, storage, and shipping.

Transdermal and inhalation:

Phthalates can pass through the skin and be absorbed transdermally or inhaled.[ref]

• Phthalates are a component of many artificial fragrances. Thus, shampoos, lotions, cosmetics, and other personal care products often contain artificial fragrances, and thus phthalates.
• Phthalates are also found in face masks and can be absorbed through skin contact as well as inhalation.[ref]
• Kids spend a lot of time on the floor, playing, and tend to have more “hand-to-mouth” behavior. Vinyl flooring in homes is linked to a 15-fold higher phthalate level in children compared to kids living in homes with other flooring materials.[ref]
• Phthalate exposure is also higher in certain workplaces. For example, phthalates are used as a plasticizer in nail polish, and inhaling nail polish fumes by nail salon workers is linked to high phthalate levels in their urine.[ref]

Oral routes of exposure:

Phthalates are pervasive in the food supply due to leaching from packaging and processing materials, such as PVC used in food processing and storage.[ref]

In the US, phthalates are allowed by the FDA in food packaging and processing materials. In contrast, the EU has restricted the use of phthalates in materials in contact with food since 2009.[ref]

Some drugs use phthalates as plasticizers in their capsules or coatings. Even if they were not intentionally added to drugs, a recent study in China found varying levels of phthalates in all of the medications they tested.[ref][ref]

Going in-depth on phthalate research in humans:

Below are just some of the thousands of studies on phthalates. As with most environmental factors, phthalates are likely to affect people differently based on their genetic susceptibility.[ref]

ADHD and Autism Spectrum Disorder:

• In children with dopamine receptor variants, higher phthalate levels are linked to significant changes in executive function.[ref]
• Higher levels of phthalates in mothers are linked to a threefold increased relative risk of ADHD diagnosis in their children at age 3.[ref]
• A 2025 study found that higher genetic susceptibility to inflammation, as well as higher phthalate exposure in utero, increases the risk of autism or neurodevelopmental problems by more than two-fold.[ref]

Infertility:

• Research shows lower odds of in vitro fertilization working for those with higher phthalate levels. This study found that those in the top quartile for phthalate metabolites had about half the chance of IVF working.[ref]
• Another recent study also showed that women in the top quartile for phthalate metabolites had less than half the normal chance of IVF resulting in a pregnancy.[ref]
• Women with phthalate metabolite levels in the second and third quartiles had twice the risk of infertility compared to women with lower phthalate levels.[ref]

Lower Testosterone:

• Low-dose, long-term exposure may decrease male fertility and testosterone levels.[ref][ref]
• Higher levels of phthalate metabolites during late puberty are associated with poorer semen quality. The highest quintile had “30% lower sperm concentration, 32% lower count and 30% lower progressive motile count, compared to men in the lowest quintile”.[ref]

Obesity and weight gain:

• Weight gain: Contaminated dust containing phthalates (found in all of the household dust samples) was found to cause human cells to produce triglycerides and cause mice to become fat.[ref]
• Fat accumulation: Previous studies in cells have found similar results for phthalates promoting fat accumulation.[ref]
• Obesity –> diabetes: One way to understand the impact of a substance on a population is to put a price on it. A recent European study calculated the cost of obesity caused by phthalates and found that phthalate exposure caused ~54,000 extra cases of obesity in women with an associated cost of €15.6 billion.[ref][ref]
• Metabolic syndrome: A large study looked at phthalate metabolite levels in over 2,000 women in relation to sex hormones and BMI. The results showed that higher levels of phthalates were associated with obesity and metabolic syndrome. In addition, the researchers found that SHBG levels were lower in women with higher levels of phthalate metabolites. [ref]

Thyroid function affected by phthalates:

• Depressed thyroid function: Several studies link urinary phthalate levels to depressed thyroid hormone levels.[ref][ref]
• Subclinical hypothyroidism: A Korean study found phthalate metabolite levels correlated with lower FT4, FT3, and slightly higher TSH levels.[ref]
• In pregnant women, higher phthalate metabolite levels are associated with lower free T4 levels as well as altered TSH/FT4 ratios. The conclusion was that “exposure to phthalates may interfere with the thyroid system during pregnancy.”[ref]
• May not be showing up in common thyroid tests: Animal studies show that phthalates decrease T4, T3, and TRH but not TSH.[ref] Most doctors prescribe thyroid medications based on TSH, so if phthalates are messing with free T3 and free T4 but not TSH, there could be a lot of people with lower thyroid function that doctors are missing.

Uterine fibroids:

• Several studies have linked phthalates and other endocrine disruptors to fibroids and uterine problems. Although most of the studies seem to be small or rely on self-reported cases of fibroids, the studies all point to the same thing – a link between endocrine-disrupting phthalate metabolites and fibroids.[ref]
• Again, putting a price tag on the problem can give a bigger picture of what is happening. A 2016 study estimated that the cost of fibroids due to this endocrine disruptor was 1.3 billion euros in the EU.[ref]
• Not everyone is at the same risk: One study found that women with certain CYP17A1 and ESR1 variants had higher phthalate levels and a higher risk of fibroids.[ref]

Histamine / Mast Cell / Allergy connection:

• Histamine release: Phthalates increase histamine release from IgE in mast cells.[ref]
• There are atopic dermatitis and the FLG gene polymorphism connections and interactions.[ref]
• Itchy skin: Another study found that higher phthalate exposure more than doubled the risk of atopic dermatitis.[ref]
• Dust allergies: A known connection has existed between phthalates in dust and allergies for more than ten years, with good studies backing it up.[ref]
• One more study replicated the finding that higher phthalate levels (flooring, dust, etc.) correlate with higher allergy levels.[ref]

Mental Health and Phthalate Exposure:

• A study of more than 11,000 participants found that higher levels of metabolites were associated with an increased relative risk of depression in adults.[ref]
• In adults over the age of 60, higher levels of phthalates were linked to a more than twofold increase in the relative risk of depression.[ref]
• Higher maternal phthalate levels correspond with higher rates of mental health diagnoses in their children.[ref]
• Elevated phthalate levels are also linked to the risk of postpartum depression.[ref]

How can we get rid of (detoxify) phthalates?

Phthalates are metabolized fairly quickly and are excreted in urine, sweat, and feces. Research shows us that the half-life of phthalates can range from hours to several days. [ref]

Phthalate detoxification is a two-step process:[ref]

• Phase I detoxification: making the molecules more water-soluble
• Phase II detoxification: attaching other chaperone compounds for elimination from the body.

Phase I metabolism involves hydrolysis by lipases, which are enzymes produced in the pancreas and stomach, and esterases. Some phthalates are also metabolized by CYP2B6.[ref]

The next step in phthalate detoxification is oxidation. The oxidative metabolites can then undergo glucuronidation reactions in phase II metabolism.[ref]

This second phase of detoxification is where genetic variants come into play. It is common to have variants that impact the specific phase II detoxification genes, and understanding these variants can help you find ways to eliminate phthalates from the body more quickly.

Lifehacks for detoxifying phthalates:

Lifestyle changes for avoiding phthalate exposure:

Glass storage containers:
Avoid storing and heating food in plastic.

Dust and vacuum regularly:
Frequent dusting decreases phthalates in the air at home.[ref] However, make sure you aren’t using furniture polish or a spray that contains phthalates as a fragrance. Try dusting the old-fashioned way with a damp rag. Vacuum regularly with a HEPA-filtered vacuum.

Food that isn’t pre-packaged:
Studies have shown that almost all packaged and processed foods contain low levels of phthalates. Buying fresh foods from local farmers at a farmer’s market or farm stand should help to reduce phthalate exposure.

Go fragrance-free:
Many artificial fragrances contain phthalates, so avoiding air fresheners (or switching to essential oils) can help. This also applies to laundry products (detergents, fabric softeners) with artificial fragrances and scented candles.

Should you only eat organic?
Vegans who eat only organic foods have slightly lower levels of phthalates.[ref] However, this could be due to eating more fresh fruits and vegetables, which aids in phase II detoxification. Going with foods that aren’t packaged (conventional or organic) could be the answer instead.

Look for Free and Clear:
Stop using dryer sheets or laundry detergent with fragrances. Go with the ‘free and clear’ laundry options. If you like your clothes to smell nice from the dryer, add a few drops of high-quality essential oil on a cloth rag and toss it in when you dry. Laundry fresh from the line smells great, so try hanging your clothes out to dry in the sunshine when you can.

Check nail polish labels:
Phthalates are found in some brands of nail polish and can be absorbed through your nails and when breathing in fumes from the polish.[ref][ref]

When reading labels, there are multiple acronyms and types of phthalates:

• DEP (diethyl phthalate)
• DBP (dibutyl phthalate) 
• DINP (diisononyl phthalate) 
• DMP (dimethyl phthalate)
• DEHP (di-2-ethylhexyl phthalate) 
• DNOP (di-n-octyl phthalate) 
• DIDP (diisodecyl phthalate) 

Kids products:
If you have young kids, phthalates are commonly found in the following (check labels!):

• Personal care products for babies: baby shampoo, wipes, baby soap, baby lotion, and diapers
• Toys: inflatables, rattles, teething rings, and any soft vinyl toys
• Vinyl: crib mattress covers or waterproof pads

Eliminating phthalates from your body:

Related Articles and Topics:

BPA: How Your Genes Influence BPA Detoxification

Phase I and Phase II Detoxification Pathways Explained

Should you eat organic? Detoxifying Organophosphates