Prospective Evaluation of Topical Almond Oil vs Hydroquinone

Prospective Evaluation of Topical Almond Oil vs Hydroquinone on the Appearance of Facial Pigmentation and the Stability of the Microbiome

The purpose of this study is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.

Study Overview

• Status: Recruiting
• Conditions: Skin Pigmentation
• Intervention / Treatment: Other: Almond Oil; Drug: Hydroquinone Topical

Detailed Description

The purpose of this experiment is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.

There will be a total of 50 subjects:

• 25 randomized to receive almond oil nightly
• 25 randomized to receive 2% hydroquinone nightly

Study Timelines:

• The duration of an individual subject's participation will last from the day of the consent/screening (visit 1) until visit 5 where they will have images taken and measurements collected to assess skin pigment, skin hydration, sebum excretion rate.
• The duration of participation is 4 months.
• The estimated time for the investigators to complete primary analysis is 2 years.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Alexis Carrington; Email: aecarrington@ucdavis.edu
• Study Contact Backup: Name: Iryna Rybak; Phone Number: 916-551-2636; Email: irybak@ucdavis.edu

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95816
      • Recruiting
      • UC Davis Department of Dermatology, Clinical Trials Unit
      • Contact: Alexis Carrington, MD; Phone Number: 916-551-2636; Email: aecarrington@ucdavis.edu
      • Principal Investigator: Raja K Sivamani, M.D.
      • Contact: Iryna Rybak, BS; Phone Number: 916-551-2636; Email: irybak@ucdavis.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Premenopausal women of Fitzpatrick skin types 3 to 6

Exclusion Criteria:

• Those with a nut allergy
• Smoking is an independent risk factor and serves as a confounder for the development of facial aging [18]. Therefore current smokers, those that have smoked within the past year, and former smokers with greater than a 20 pack year history of smoking will be excluded.
• Those with an autoimmune photosensitive condition or a known genetic condition with a deficiency in collagen production (such as Ehlers-Danlos syndrome) will be excluded as this can be a confounder for facial photoaging.
• Hormonal medications or therapies will not be allowed unless they have been stable on their medications for at least 2 months. Examples include oral contraceptives, progesterone-based injections, and estrogen based hormonal replacement therapy.
• Those who have undergone any cosmetic procedures to the face in the 4 months prior to enrollment in the opinion of the investigator. People that have undergone deeper chemical peels (TCA based peels) within 1 year prior to enrollment will also not be eligible.
• Individuals who are unwilling to discontinue vitamin E containing supplements and food sources during the washout and intervention.
• Individual who are unwilling to discontinue topical cosmetic products during the duration of the study.

• Individuals who are not willing to engage in a two-week washout on topical treatments known to affect facial pigmentation and these agents will be restricted during the study period as well. These include topicals that contain:

  • Retinoids such as tretinoin, adapalene, retinol.
  • Antioxidant ingredients such as vitamin C or vitamin E.
  • Pigment-reducing agents such as hydroquinone, azelaic acid, kojic acid per the discretion of the investigator except for the hydroquinone that is provided in this study.
  • Topicals that contain a nut oil or nut extract as part of their ingredient list.
• Furthermore, subjects will be asked to refrain from use of any other topical products for one week prior to each visit apart from the study agents supplied from this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Almond oil; Almond Oil Pressed Cold	Other: Almond Oil; Almond oil
Active Comparator: Hydroquinone; Hydroquinone 2% cream	Drug: Hydroquinone Topical; Hydroquinone 2% cream; Other Names: Hydroquinone

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intensity of facial pigment	Facial images will be obtained and analyzed with the BTBP image analysis system	16 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Shifts in the microbiome diversity (Shannon index as an example)	The skin microbiome will be analyzed to assess any changes after topical almond oil application, compared to the use of topical hydroquinone.	16 weeks
Quantification for the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia	The skin microbiome will be analyzed to assess the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia	16 weeks
Appearance of facial redness	The research team will quantify the presence of facial redness with a SkinColorCatch from Delfin Technologies. This will measure the RGB colors and average them from each participant for each of the visits. Skin pigment, including the presence of redness, will be measured using a SkinColorCatch from Delfin Technologies. This device shows the RGB Colors, CIE L*a*b* and L*c*h* color space coordinates when the device is applied to the skin.Included is the link to the device (http://www.truesystem.co.kr/product/pdf/SkinColorCatch%20Brochure%202016.pdf).	16 weeks
Subjective tolerability assessment	A questionnaire that assesses for stinging, itching, and burning will be utilized.	16 weeks
Intensity of facial pigment	Facial images will be obtained and analyzed with the BTBP image analysis system	8 weeks

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Raja Sivamani, MD MS AP, UC Davis Dermatology

Publications and helpful links

Helpful Links

• Learn more or sign up for the study here!

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2021
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: March 5, 2021
• First Submitted That Met QC Criteria: May 1, 2021
• First Posted (Actual): May 6, 2021

Study Record Updates

• Last Update Posted (Estimated): September 12, 2025
• Last Update Submitted That Met QC Criteria: September 10, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Skin Diseases; Pathological Conditions, Signs and Symptoms; Skin and Connective Tissue Diseases; Pigmentation Disorders; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Antioxidants; Protective Agents; Radiation-Protective Agents; almond oil; hydroquinone
• Other Study ID Numbers: 1666478

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No