What Blood Tests Should You Get for Persistent Acne?

Key Takeaways

Persistent acne that doesn't respond to skincare or prescriptions is often driven by internal imbalances that topical treatments can't reach
The five most relevant biomarkers to test are testosterone, DHEA-S, cortisol, insulin, and Vitamin D
Standard dermatology visits almost never include these tests — they are not part of a typical skin exam workflow
At-home dried blood spot testing now makes biomarker testing accessible without a doctor referral
Understanding your specific imbalances is the starting point for a treatment plan that actually addresses the cause

If you have tried prescription topicals, antibiotics, hormonal birth control, and a careful skincare routine — and you are still breaking out the problem is probably not on your skin. It is inside your body, in the biological systems your skin is responding to.

Certain internal imbalances — hormonal, metabolic, and nutritional show up as acne because the skin is a reflection of your internal biology. The breakouts are not the problem. They are the symptom. And the most direct way to find the actual problem is to measure it.

Here is what to test, why each marker matters, and how to access that testing without navigating a complicated path through specialists.

Why Standard Dermatology Visits Don't Include Blood Tests

The conventional dermatology model is built around skin examination and prescription management — not internal investigation. A dermatologist's training and workflow centers on what is visible and treatable from the outside: bacteria, inflammation, oil production, follicle health.

Blood panels for hormones and metabolic markers fall outside that scope. They add time to an appointment designed for efficiency, require lab orders and follow-up visits, and often involve insurance complications. For the majority of acne patients — particularly teenagers whose breakouts are straightforwardly puberty-driven — this approach works well enough.

But for the significant subset of people with adult-onset acne, persistent cystic breakouts, or acne that keeps returning after prescription treatment, the conventional model leaves a critical gap. The question why is never asked because the workflow is not designed to answer it.

The 5 Biomarkers Most Linked to Persistent Acne

These are the markers that matter most. Not every person with acne needs all of them, but together they cover the most common internal drivers of stubborn breakouts.

Testosterone and Free Testosterone

Testosterone is the most well-established hormonal driver of acne. It stimulates the sebaceous glands — the oil-producing structures inside pores — to increase output. More oil means more clogged pores. More clogged pores means more breakouts.

Critically, the total testosterone level in your blood is not the full picture. What matters most is free testosterone — the portion not bound to sex hormone-binding globulin (SHBG). Two people can have identical total testosterone readings but dramatically different breakout patterns depending on their SHBG levels. Someone with low SHBG effectively has more active testosterone available to stimulate oil production, even if their "total testosterone" looks normal on a standard panel.

This is one of the most common reasons people are told their "hormones are normal" by a dermatologist — but their acne says otherwise.

DHEA-S (Dehydroepiandrosterone Sulfate)

DHEA-S is a hormone produced by the adrenal glands that converts to testosterone directly within skin tissue. This is why it is often the underlying culprit when testosterone levels appear normal. The conversion happens locally, at the skin, which means it doesn't necessarily show up in blood testosterone measurements — but it is still driving excess oil production and breakouts.

Elevated DHEA-S is particularly common in acne that is concentrated along the jawline and chin, and in acne that worsens under physical or psychological stress, since the adrenal glands ramp up DHEA-S production during stress responses.

Cortisol

Cortisol is your body's primary stress hormone, produced by the adrenal glands in response to physical or psychological stressors. It drives acne through two pathways. First, it directly stimulates sebaceous gland activity — elevated cortisol tells oil glands to produce more sebum. Second, it triggers a cascade that increases androgen production, meaning it compounds the testosterone and DHEA-S picture described above.

People with chronically elevated cortisol — whether from sustained work stress, poor sleep, intense exercise, or persistent psychological pressure — often have a pattern of acne that flares with stress and never fully clears during periods of high demand.

Standard lifestyle advice ("manage your stress") is unhelpful unless you know whether cortisol is actually elevated. Measuring it gives you a real signal to act on.

Insulin and Blood Sugar Markers

Insulin resistance creates a hormonal domino effect that feeds directly into acne. When insulin is chronically elevated — usually as a result of a high-glycemic diet or underlying metabolic dysfunction — it suppresses SHBG and increases androgen production. It also elevates IGF-1, a growth factor that accelerates skin cell turnover and sebum production.

The result is that someone with insulin resistance is effectively amplifying the hormonal signals driving their acne at a systemic level, regardless of what they are putting on their skin.

Up to 81% of people with stubborn acne show early signs of insulin resistance — yet this is almost never screened for in standard acne care. For a deeper look at exactly how this mechanism works, see our detailed article on how blood sugar impacts your skin.

Vitamin D

Low Vitamin D is one of the most overlooked contributors to persistent acne. Vitamin D functions as a hormone-like regulator in the skin, supporting the immune response that keeps inflammatory acne in check and the repair processes that heal existing breakouts faster. Deficiency weakens both of these functions.

Multiple studies have found significantly lower Vitamin D levels in people with acne compared to clear-skinned controls, with the association strongest for inflammatory and cystic acne. Deficiency is widespread — particularly in northern latitudes, during winter months, and in people who spend most of their time indoors.

Testing Vitamin D is one of the simplest, most actionable tests available. Deficiency is straightforward to correct with supplementation, and the skin response is often noticeable within weeks of reaching optimal levels.

How to Request These Tests Through Your Doctor

If you prefer to go through a primary care physician or OB-GYN, you can request these specific tests:

Free and total testosterone
DHEA-S (DHEA sulfate)
Morning cortisol (serum or salivary)
Fasting insulin and HbA1c
25-OH Vitamin D

Some providers will order these without pushback, particularly if you present with a pattern of acne that has not responded to conventional treatment. Others may be resistant, particularly for cortisol and DHEA-S which are less commonly ordered in dermatology-adjacent conversations.

It is worth being direct: "I have persistent acne that hasn't responded to topical or systemic treatments, and I would like to rule out internal hormonal and metabolic drivers." Framing it as a process of elimination rather than a challenge to their expertise tends to work well.

Insurance coverage varies significantly. Hormone panels are more likely to be covered if ordered in the context of menstrual irregularities, PCOS evaluation, or metabolic health concerns all of which frequently co-occur with hormonal acne.

At-Home Options: How Dried Blood Spot Testing Works

If navigating the conventional system feels like a barrier, at-home biomarker testing is now a genuinely accurate alternative. Dried blood spot (DBS) testing — the method used by BreakoutLabs — involves collecting a few drops of blood from a finger prick onto a collection card, allowing it to dry, and mailing it to a CLIA-certified laboratory in a prepaid prepaid mailer.

This method has been validated in clinical research for over 30 years and produces results that are directly comparable to standard venous blood draws for the hormone and metabolic markers most relevant to acne. The samples are analyzed in the same certified labs used by hospitals and clinics, with physician review before results are released.

The BreakoutLabs Acne Root Cause Test measures all five biomarker categories covered in this article — testosterone, DHEA-S, cortisol, insulin, and Vitamin D — from a single at-home sample, with results in 7–10 business days delivered through a personalized dashboard.

How to Use Your Results

A list of numbers without context is not useful. What matters is knowing what your specific pattern of results means for your acne, and what to do about it.

Results showing elevated testosterone with low SHBG point toward androgen-reducing strategies — which might include dietary changes (reducing insulin load, which suppresses androgens), specific supplements like zinc and spearmint, or targeted prescription options like spironolactone.

Elevated cortisol points toward adrenal-support strategies — sleep optimization, stress management protocols, adaptogenic supplements, and reducing high-intensity exercise if overtraining is a factor.

Vitamin D deficiency is the most straightforward to address: supplementation at doses appropriate to your deficiency level, with follow-up testing in 8–12 weeks.

Insulin resistance requires dietary changes as the primary intervention — specifically reducing glycemic load, improving meal timing, and addressing any underlying metabolic patterns. The hormonal acne diet guide covers this in detail.

Frequently Asked Questions

What blood tests should I ask my doctor for if I have persistent acne? The most relevant tests are free and total testosterone, DHEA-S, morning cortisol, fasting insulin, HbA1c, and 25-OH Vitamin D. Together, these cover the four most common internal drivers of stubborn acne: androgen excess, adrenal/stress hormones, metabolic dysregulation, and nutrient deficiency.

Can hormones cause acne even if my periods are regular? Yes. Regular periods indicate that estrogen and progesterone are cycling normally — but testosterone and DHEA-S can be elevated independently of menstrual regularity. Many people with regular cycles still have elevated free testosterone or DHEA-S levels that drive persistent breakouts, particularly along the chin and jaw.

Is at-home hormone testing as accurate as a lab draw? For the markers most relevant to acne — testosterone, DHEA-S, cortisol, insulin, and Vitamin D — dried blood spot testing produces results that are clinically comparable to venous blood draws. All BreakoutLabs samples are processed in CLIA-certified labs, the same standard required of hospital and clinical laboratories.

How long does it take to get results from an at-home acne test? BreakoutLabs delivers results in 7–10 business days from when the sample arrives at the lab, accessible via a secure online dashboard.

Does insurance cover hormone testing for acne? Coverage varies widely. Insurance is more likely to cover hormone panels when ordered through a physician in the context of a specific diagnosis or clinical concern — PCOS evaluation, menstrual irregularities, or metabolic screening. At-home testing through BreakoutLabs is HSA/FSA eligible.

Your BreakoutLabs results include a Clear Skin Blueprint that explains exactly what each marker means for your skin and what specific actions to take based on your individual pattern.