Research reviewed by Gram found that women with higher blood levels of certain PFAS “forever chemicals” in midlife had slightly lower muscle mass, with a drop of about 0.04 kg/m2 per 0.2 ng/mL increase in PFNA. The effect was small, and muscle strength was not clearly affected. Scientists call this a link, not proof of cause.
Gram Research analysis of a large study from the Project Viva cohort looked at whether PFAS, a group of everyday chemicals often called forever chemicals, are linked to muscle mass in women around age 50. The study followed 551 women and measured PFAS in their blood, both during pregnancy and at midlife. Muscle mass was measured with a low-dose scan similar to a bone density test. Women with higher levels of a few specific PFAS had slightly less muscle mass, but the difference was very small. Grip strength and physical performance were not worse, and in some cases were slightly better. The researchers say these results show a link, not proof that the chemicals cause muscle loss, so more research is needed before people change their habits because of them.
Key Statistics
A 2026 cohort study of 551 women in midlife found that higher blood levels of the PFAS chemical PFNA were linked to a small drop in muscle mass, about 0.04 kg/m2 for every 0.2 ng/mL increase.
In the same 2026 study, women with higher PFAS levels in midlife showed grip strength and physical performance that were unchanged or slightly better, not worse.
The 2026 Project Viva study reported an average muscle mass score of 6.93 kg/m2 among its 551 midlife women, with a standard deviation of 1.11.
The Quick Take
- What they studied: Researchers wanted to know whether higher levels of PFAS, chemicals that persist in the environment and in the body, are linked to less muscle in women in midlife, and whether these chemicals affect how strong and physically capable those women are.
- Who participated: The study included 551 women from the Project Viva cohort, a long-running research group. Their average age at the midlife measurements was about 50.7 years. Blood samples were taken during pregnancy, which began between 1999 and 2002, and again at midlife, with midlife data collected from 2017 to 2024.
- Key finding: Women with higher blood levels of PFNA, PFDA, and PFUnDA, three types of PFAS, had slightly lower muscle mass. For PFNA, muscle mass dropped by about 0.04 kg/m2 for every 0.2 ng/mL increase in blood level. That is roughly 0.6 percent of the average muscle score of 6.93 kg/m2, so the change was small. Muscle strength and physical performance were not clearly affected.
- What it means for you: This study does not show that PFAS will weaken your muscles, and the effect it found was small. It does suggest that PFAS exposure may be one of many factors that influence muscle health in midlife. Maintaining muscle through regular strength training, enough protein, and daily movement is well supported for healthy aging, regardless of these findings.
The Research Details
This study used data from Project Viva, a group of women who joined a research project during pregnancy between 1999 and 2002. Researchers took blood samples from these women during pregnancy to measure PFAS levels. Many years later, between 2017 and 2024, the same women returned for midlife visits, when researchers measured their PFAS levels again and assessed their muscle health.
To measure muscle, the team used a scan called dual X-ray absorptiometry, which is similar to a bone density test and estimates how much lean muscle a person has in their arms and legs. They divided this result by height squared to create a score called appendicular lean mass index, or ALMI. They then used statistical models that adjusted for other factors that could affect muscle, such as age and body size, to see whether PFAS levels were linked to ALMI. They also tested a combined PFAS score, which looks at several chemicals together.
The researchers also checked whether menopause status, diet, or physical activity changed any link between PFAS and muscle. In additional analyses, they looked at grip strength and physical performance tests at midlife, and at whether PFAS levels during pregnancy were linked to muscle later in life.
Because the study followed the same women over many years and measured PFAS at two time points, it could look at both early and later exposure. This design helps scientists see whether chemical levels line up with muscle changes over time, rather than only at a single moment. Using a standard scan to measure muscle also makes the results easier to compare with other studies.
The study has several strengths. It used a well-established research group, measured muscle with a standard scanning method, and compared its PFAS levels with those from national U.S. health surveys, which suggests the blood levels were typical. The researchers also tested multiple statistical approaches and checked several possible influencing factors. However, this type of study can show that two things are linked but cannot prove that one causes the other. Results from one study of 551 women should be viewed as early evidence that needs to be confirmed by other research.
What the Results Show
The main finding is that women with higher blood levels of some PFAS in midlife had slightly lower muscle mass. The clearest signals came from PFNA, PFDA, and PFUnDA, three of the PFAS types measured. When the researchers looked at PFNA alone, muscle mass dropped by about 0.04 kg/m2 for every 0.2 ng/mL increase in blood level. The confidence range for this number was narrow and just reached the line of no effect, which means the result is statistically borderline.
The researchers also looked at the combined PFAS score and found a similar pattern. Women with higher overall PFAS levels had slightly lower muscle mass. However, the size of this difference was small compared with the normal range of muscle mass among women in midlife. The average muscle score in the study was 6.93 kg/m2, with a typical spread of 1.11, so the PFAS-related drop was a small fraction of normal variation.
The researchers checked whether menopause, diet, or physical activity changed the link between PFAS and muscle. They did not find consistent evidence that any of these factors made the link stronger or weaker. This suggests the pattern did not depend on whether women had gone through menopause or on their eating or exercise habits, although the study was not large enough to test every subgroup carefully.
Finally, the researchers did not find that PFAS was linked to weaker strength or performance. Grip strength and physical performance measures were unchanged or slightly better in women with higher PFAS levels. The team also found no harmful link between PFAS levels during pregnancy and muscle mass at midlife.
Beyond the main muscle mass result, the study looked at how PFAS related to real-life physical function. Grip strength and physical performance tests showed no meaningful decline with higher PFAS exposure. Some results even leaned slightly positive, which is most likely due to chance or to other factors the study did not fully account for. This matters because muscle mass alone does not always predict how strong or mobile someone is, so the lack of functional decline is a reassuring detail.
PFAS levels measured during pregnancy did not show a harmful link to muscle mass decades later. This suggests that the timing of exposure may not be the main driver of the small muscle differences seen at midlife, although this question needs more study before any firm conclusion can be drawn.
Earlier research has linked PFAS to changes in hormones, inflammation, and body composition, and some studies have connected these chemicals to other health outcomes in adults. This study adds to that body of work by focusing specifically on muscle in midlife women, a group at risk of frailty. Its findings are consistent with the idea that PFAS may have small effects on body tissues, but the link found here is modest and not as strong as some earlier signals in other health areas. Scientists will need to compare these results with other large cohort studies to see whether the pattern holds across different groups of people.
The study was observational, which means the researchers observed what happened rather than assigning people to different PFAS exposures. Because of this, other factors that were not measured or fully accounted for could explain some of the link. PFAS levels were measured from blood at only a few time points, so they may not fully reflect long-term exposure. The muscle differences were small, and the study may have been too small to detect some patterns, especially within subgroups like women who had gone through menopause or those with different activity levels. The researchers also tested many possible links, which increases the chance that some results appeared significant by coincidence. Finally, the participants were a specific group of women in one research cohort, so results may not apply equally to all women or to men.
The Bottom Line
Based on this single study, the evidence that PFAS affect muscle is weak and preliminary, so confidence in any specific change should be low. The findings do support the general idea that scientists should keep studying PFAS and muscle health together. For individuals, the most reliable advice remains the same as before: keep your muscles strong through regular resistance training, eat enough protein, stay active, and talk with a doctor about any concerns. Reducing everyday PFAS exposure, such as limiting use of nonstick cookware and checking local water advisories, is a reasonable precaution for overall health, but this study alone does not prove it will protect muscle.
Women in midlife and older adults who are concerned about muscle loss, frailty, or chemical exposures may find this research interesting. Clinicians, researchers, and public health officials who track environmental chemicals may also want to follow these findings. People who already have a clear plan for strength, nutrition, and activity can keep following it. This study is less relevant for people looking for a specific treatment, because it did not test ways to lower PFAS or protect muscle directly. Anyone with a medical condition that affects muscle or kidney function should speak with a healthcare provider before making changes.
Muscle mass changes slowly, usually over months to years of consistent training and nutrition, so any benefit from strength work would appear gradually. PFAS also leave the body very slowly, often over several years, so changes in exposure would take a long time to show up in blood levels. Because this study looked at associations over decades, it cannot tell us how quickly any effect might reverse. Realistic expectations are months of steady habits before noticeable strength gains, and years before scientists could confirm whether reducing exposure makes a measurable difference.
Frequently Asked Questions
Do forever chemicals cause muscle loss in women?
A 2026 study of 551 women in the Project Viva cohort found only a weak link. Higher blood levels of some PFAS were tied to slightly lower muscle mass, but the drop was small, about 0.04 kg/m2 for PFNA. The study shows an association, not proof that PFAS cause muscle loss.
What are PFAS chemicals and where do they come from?
PFAS are a group of man-made chemicals used in nonstick cookware, stain-resistant fabrics, and some food packaging. They break down very slowly and can build up in the body over time. The study’s blood levels were comparable to those in national U.S. health surveys from the same period.
Can I protect my muscle mass from PFAS exposure?
The study did not test ways to lower PFAS or protect muscle, so it cannot say what works. Strength training and enough protein are widely recommended for keeping muscle in midlife. The study found no consistent evidence that diet or physical activity changed the PFAS and muscle link.
How much muscle mass do midlife women typically have?
In this study of 551 women with an average age of 50.7, the average appendicular lean mass index was 6.93 kg/m2, with a standard deviation of 1.11. This score reflects lean muscle in the arms and legs, measured with a DXA scan. Higher values generally indicate more lean muscle.
Want to Apply This Research?
- Log resistance training sessions each week, aiming for at least two sessions covering the major muscle groups, and record the number of days you complete them. Track daily protein intake in grams and aim for a consistent target that a doctor or dietitian recommends. Once a month, record a simple strength measure such as the number of chair stands you can do in 30 seconds, and note any changes over time.
- Set a weekly reminder for two strength training sessions and pair them with a regular activity such as walking. Use the app to build a simple meal plan that includes a protein source at each meal. If you cook often, consider reviewing which nonstick or food storage products you use and make gradual swaps if you choose to, while keeping your overall diet balanced and varied.
- Review your app data every three months to spot trends in strength, activity, and protein intake. Repeat a simple strength test every few months and bring the results to your annual checkup so your provider can see changes over time. Keep a running note of any new exposures or product changes, and update your plan as new research on PFAS and muscle health is published.
This article summarizes one observational study and is for general information only. It does not prove that PFAS cause muscle loss and is not medical advice. Talk with a doctor or registered dietitian before changing your diet, exercise routine, or health plans, especially if you have concerns about muscle health or chemical exposure.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.