A 2023 study of more than 2,000 heterosexual couples found that women's allostatic load markers — the measurable burden of stress on the body — tracked their male partners' more strongly than the reverse, and the association persisted in both happy and unhappy relationships. The finding gives scientific weight to a claim spreading across TikTok and Instagram: the wrong boyfriend can make you look worse.

Consider Sarah*, a 23-year-old from Australia. About six months into her last relationship, she rapidly lost 11 pounds and woke regularly with nausea or acid reflux. "My hair was thin and dry; you wouldn't have known I had curly hair because the texture completely changed, and I had the most frustrating bumps and pimples all over my forehead," she says. A month after the two-year relationship ended, her pimples disappeared and her curls returned. "Now I've never looked better or felt more confident," she says.

What are women on social media saying?

Creator Snarly Carly posted a TikTok video explaining the phenomenon in platform parlance, drawing an emphatic comment section. Another creator, @heyitsmekmac, described her own "glow-down": "The wrong men make you ugly. My face was broken out, the cortisol levels were high, water weight was through the roof… If he's stressing you out, he gotta go."

Women on Instagram and Reddit separately told Allure their male partners had a damaging effect on their appearance. Research into psychology, health and relationships already supports the notion: in heterosexual relationships, women who receive appearance-related criticism from a partner report diminished self-worth and reduced relationship satisfaction.

What does stress actually do to skin and hair?

Research indicates stress is a key driver of cosmetic issues like acne and hair loss. Keira Barr, MD, a board-certified dermatologist and founder of Center for Mind Skin Medicine in Bend, Ore., said there is a physiological mechanism behind the anecdotes. "Heightened cortisol levels and inflammatory signaling can send the skin down a path of breakouts, sensitivity, dehydration, dullness, slower healing, and a generally less rested appearance," she says.

The toll goes deeper than the surface. Researchers have found the psychosocial impact of thinning hair provokes anxiety disproportionate to its "objective severity" — meaning women can become distressed by changes others barely notice. Generally, once the stressor — in these cases, the male partner — is removed, women start to feel like themselves again.

Why do women carry more of the physical cost?

Psychotherapist Laurel Steinberg, PhD, points to the unequal mental and emotional load women are expected to carry in heterosexual relationships. When partners live together, society often expects women to shoulder the burdens of home life. "When the culture at home is strained, women can feel more guilt and shame than their partners, leading them to experience chronic stress and poorer health markers," she says.

That inequity hits the body, not just the mind. The 2023 study, conducted by Howard University, the University of Montréal and Montréal's Mental Health University Institute, followed couples over four years and concluded women suffer a greater physiological impact from long-term relationships than men do.

Can the body reject a relationship before the mind does?

"I think it's not just possible, it's typical," says Molly Burrets, PhD, a Los Angeles-based clinical psychologist and couples therapist. She explains stress is processed first through interoception — our ambient sense of what's happening in and around our bodies — and neuroception, an internal system scanning for cues of safety or threat in tone of voice, facial expressions or the energy in a room.

"When we're in a relationship that feels unsafe, unpredictable, or emotionally depleting, our nervous system reads that as a threat, even if no one's raising a voice," Dr. Burrets says. "A nervous system that's perceiving a threat doesn't know the difference between 'my partner is criticizing me' and 'I'm being chased by a predator.' It just mobilizes."

Among her clients, chronic relationship stress has manifested as:

• chronic fatigue that doesn't resolve with sleep;
• gut issues and body tension;
• sleep disruption and frequent illness due to immune dysfunction;
• a racing heart or shallow breathing around specific triggers;
• sudden hair thinning or shedding, breakouts, dull skin, immovable dark circles, and noticeable weight shifts.

Some women report physical symptoms with blunter causes. Ava* says she "used to get UTIs like crazy" with a previous boyfriend, flaring a day or two after sex — until she caught him leaving the bathroom. "He didn't wash my hands... I jokingly said something about it, and he just turns to me and said, 'Yeah, I never really wash my hands,'" she recounts. They broke up shortly after. The UTIs never returned, even with different partners.

Is the post-breakup glow-up real?

Lara Devgan, MD, a board-certified plastic and reconstructive surgeon in New York City, says a toxic partner can keep you in a near-constant stress response. "Sometimes the most powerful beauty intervention is removing the thing that is exhausting you, whether it is a bad boyfriend or something else," she says.

Dr. Devgan adds that people often see positive physical changes after a breakup because they reinvest time in themselves, which improves sleep, nutrition and skincare consistency. Dr. Barr frames it in similar terms: "When a woman begins treating herself gently again after a relationship that didn't feel gentle, she is giving her body very different sensory and relational information. That post-breakup glow may be what it looks like when a body that has spent months or years organized around protection finally has more room for repair, restoration and connection."

Dr. Burrets hears the same pattern from clients: "I almost universally hear some version of 'I have so much more energy' — not because their life got easier, but because their nervous system isn't spending all day, every day, scanning for threat. That vigilance is exhausting, even when you're not consciously aware you're doing it."

The "boyfriend made me ugly" posts, in short, are not an empty trend. Between the cortisol data and the dermatologists' clinical observations, women now have physiological evidence to add acne, shedding and chronic fatigue to the list of reasons to leave.

*Indicates a pseudonym used for privacy.