Effects of Heat-Killed Lactobacillus acidophilus IDCC 3302 on Skin Aging Parameters: A Randomized, Double-Blind, Placebo-Controlled Trial in Healthy Adults.

Heat-killed L. acidophilus IDCC 3302 (ID-ACT 3302) showed no superiority over placebo for the primary endpoint of crow's-feet wrinkle reduction at 12 weeks.

• The trial was a 12-week, randomized, double-blind, placebo-controlled design with 100 participants assigned to either ID-ACT 3302 or placebo.
• The prespecified primary endpoint was change in crow's-feet wrinkles assessed using investigator visual wrinkle grading and PRIMOSlite.
• Wrinkle grade improved over 12 weeks in both groups, but no between-group superiority was demonstrated for ID-ACT 3302.
• Participants were healthy adults with periorbital wrinkles.

The overall skin elasticity index R2 showed a statistically significant inter-group difference favoring ID-ACT 3302, though this finding is considered exploratory.

• R2 (overall elasticity index measured by Cutometer) exhibited a significant inter-group difference between the ID-ACT 3302 and placebo groups.
• Secondary endpoints were not adjusted for multiplicity, making the R2 finding hypothesis-generating rather than confirmatory.
• The effect size for R2 was described as small.
• Other elasticity indices R5 and R7 improved consistently in both groups without significant inter-group differences.

Skin hydration, transepidermal water loss (TEWL), and global assessment scores improved in both the ID-ACT 3302 and placebo groups over 12 weeks without significant between-group differences.

• Hydration, TEWL, R5, R7, and global improvement scores all improved over the 12-week period.
• These improvements were observed consistently in both the active and placebo groups.
• No placebo-adjusted benefit was observed for hydration, TEWL, or global assessment scores.
• Secondary endpoints were not multiplicity-adjusted, limiting interpretability of any nominal differences.

ID-ACT 3302 supplementation for 12 weeks was safe and well tolerated, with no serious adverse events reported.

• Safety outcomes were described as comparable between the ID-ACT 3302 and placebo groups.
• No serious adverse events were observed in either group during the 12-week trial.
• The trial enrolled 100 participants in the full analysis set.
• The study authors concluded that 12-week supplementation with ID-ACT 3302 was safe and well tolerated.

Oral supplementation with postbiotics (heat-killed lactic acid bacteria) was evaluated as a potential approach to support skin homeostasis, with clinical validation noted as limited in this field.

• Skin aging is described as a multifactorial process driven by intrinsic and extrinsic factors.
• The study investigated orally administered postbiotics as a means to support skin homeostasis.
• The authors noted that clinical validation of postbiotic efficacy for skin remains limited.
• ID-ACT 3302 is described as a heat-killed lactic acid bacterium (Lactobacillus acidophilus IDCC 3302).

The authors concluded that the exploratory R2 elasticity finding requires confirmation in adequately powered trials before clinical conclusions can be drawn.

• The R2 finding was described as 'hypothesis-generating' due to lack of multiplicity adjustment and small effect size.
• The authors explicitly stated this finding 'requires confirmation in adequately powered trials.'
• The abstract characterized the between-group difference in R2 as 'exploratory.'
• No secondary endpoint findings were considered confirmatory given the absence of multiplicity adjustments.