Does Shaving Reduce Underarm Odor?What the Washing Studies Tested

If you prefer underarm hair, the research does not supply a reason to treat shaving as a hygiene requirement. Experiments using male odor donors found different results depending on which smell rating was measured.¹

The soap-washing trial measured a short-lived effect

A 2016 trial² enrolled 30 White men aged 18 to 48, after a 14-day period without deodorants or antiperspirants. Underarms received different hair-removal methods or no removal, followed by controlled washing.²

Immediately afterward, odor scores fell 57.3% with blade shaving plus washing, versus 23.5% with washing alone. These percentages describe changes in assessors’ smell ratings.²

The shaving advantage at 24 hours had P = 0.0682, outside the conventional 0.05 cutoff. The paper used a more permissive 0.10 threshold. Later washes again produced immediate benefits, but ratings 24 hours after those washes approached baseline. That is not three days of continuous odor protection. Assessors could see the hair despite nominal blinding. Procter & Gamble funded the study; all authors were employees.²

Another set of experiments found inconsistent changes

Four experiments reported in 2012 collected men’s underarm odor on pads. Women rated its intensity, pleasantness and attractiveness. The women assessed the smell; their underarms were not the ones shaved.¹

Shaving improved ratings in one experiment involving men who had not previously shaved. Two subsequent experiments in that group did not find significant differences. Comparisons involving one to three weeks of regrowth also failed to show significant differences in the relevant experiments, although much longer regrowth affected attractiveness ratings.¹

A rating of attractiveness is a different outcome from whether your work shirt smells by lunchtime. These experiments do not establish a shaving frequency for women.¹

Women’s skin research measured irritation, not odor control

A 2020 study³ recruited 66 Thai women aged 30 to 40 who already shaved, plucked or waxed regularly. 64 completed the assessments; two withdrew because waxing caused excessive irritation. Women used their usual method, with the treated side randomized. They were not randomly allocated to different hair-removal methods.³

Shaving produced more visible dryness at 30 minutes, returning to baseline by 48 hours. Plucking and waxing increased redness. The shavers used water only, which matters when comparing these results with a routine that includes shaving gel. This was a short study of selected healthy skin, not a test of daily shaving for months or years. Unilever funded it, and the authors had company employment ties.³

It supports taking skin discomfort seriously. It does not tell us which method produces the least odor in women.³

If you choose to shave, change the technique before increasing frequency

The American Academy of Dermatology’s⁴ shaving advice is to:⁴

• Soften skin and hair with water, such as after a shower.
• Use shaving cream or gel; choose a sensitive-skin formula if needed.
• Move the razor with the direction of hair growth.
• Rinse the blade between strokes and replace disposable razors or blades after 5 to 7 shaves.
• Let the razor dry between uses and store it somewhere dry.

These are skin-care recommendations, not a schedule shown to prevent odor. If you are comparing your own routines, avoid changing the razor, soap and deodorant together. Write down how the skin feels as well as when odor returns. A small difference in smell may not be worth persistent soreness to you.

Check whether the complaint is odor or wetness

The American Academy of Dermatology⁵ explains that antiperspirants reduce sweating; deodorants target odor. Identify which result you want before judging a hair-removal routine. If the problem is a soaked blouse, the odor studies above have not answered that question.⁵

Our guide to antiperspirant versus deodorant covers the product distinction. The “Dry Skin, Lights Out” section of Arms Up discusses underarm irritation and the limited shaving research. Its Fresh Log gives you a place to record where, when and under what circumstances the problem occurs.

For skin that reacts to washing, the NHS⁶ suggests asking a pharmacist about a gentler soap substitute. It advises a GP appointment when odor has not improved with self-care and affects self-esteem, changes from its usual smell, or accompanies a sudden increase in sweating. Bring those changes to the appointment instead of assuming that removing more hair will solve them.⁶