Flex (SC)™

TCM herbal formula for muscle spasms, cramps, and stiffness — skeletal muscles in the extremities; smooth muscles in the internal organs; muscle tightness from repetitive movements; external injuries with muscle sprain and strain — muscle relaxant; analgesic; anti-inflammatory; tonifies Liver yin and Liver blood; warms meridians; invigorates blood circulation

⚠️ Do not use long-term in patients with hypertension — prolonged use of Zhi Gan Cao (Radix et Rhizoma Glycyrrhizae Praeparata cum Melle) may be associated with water retention. Contains Dang Gui Wei (Extremitas Radix Angelicae Sinensis) — patients on anticoagulant or antiplatelet therapies such as Coumadin (warfarin) should use with caution or not at all.

CLINICAL APPLICATIONS

* Spasms and cramps:

§ Skeletal muscles in the extremities

§ Smooth muscles in the internal organs

* Muscle tightness and stiffness due to repetitive movements

* External injuries with muscle sprain and strain

Background: Muscle spasms and cramps are involuntary and sometimes painful contractions of the muscles, affecting many muscle groups including leg, calf, thigh, hands, arms, abdomen, and intestines. Common causes include overuse or injury of a muscle, dehydration, electrolyte imbalance, excessive alcohol consumption, certain disease states (hypothyroidism, kidney failure), and use of drugs (diuretics). Stretching and adequate intake of fluids with sufficient potassium are the best preventative measures. Flex (SC) is based on the classic formula Shao Yao Gan Cao Tang (Peony and Licorice Decoction), used for approximately 2,000 years to treat spasms and cramps of skeletal and intestinal muscles.

TCM differentiation: The etiology of muscle spasms and cramps is Liver yin and Liver blood deficiencies. Effective treatment focuses on nourishing Liver yin and Liver blood, activating qi and blood circulation, and removing stagnation. The Liver governs the tendons and sinews — when Liver yin and blood are deficient, the tendons and smooth muscles lose nourishment and become prone to spasms, cramps, and tightness.

Key herb-level clinical data:

— Bai Shao (Radix Paeoniae Alba / White Peony Root): tonifies Liver yin and Liver blood; paeoniflorin — strong analgesic, antispasmodic, and anti-inflammatory effects; anti-inflammatory — modulates pro-inflammatory mediators production from macrophage-like synoviocytes; muscle relaxant — relaxes both smooth and skeletal muscles (with Gan Cao); analgesic — effectiveness increased significantly when combined with acupuncture; clinical studies (Bai Shao + Gan Cao): leg cramps in the calf; muscle cramps in hemodialysis; restless leg syndrome; intestinal spasms; facial spasms and twitching; menstrual cramps and pain; neuralgia; trigeminal neuralgia; neck pain; acute back pain; heel pain; pain in the lower back and legs; sciatica; gastric and abdominal pain; dysmenorrhea

— Zhi Gan Cao (Radix et Rhizoma Glycyrrhizae Praeparata cum Melle / Honey-Prepared Licorice Root): harmonizes formula; nourishes and relaxes tendons and smooth muscles (with Bai Shao); anti-inflammatory — enhances glucocorticoid effect through increased production and secretion, decreased hepatic metabolism, and increased plasma concentration; clinical applications: pain, inflammation, edema, arthritis, spasms, cramps; caution with long-term use in hypertension — may cause water retention

— Dang Gui Wei (Extremitas Radix Angelicae Sinensis / Angelica Sinensis Tail): warms peripheral channels and collaterals; invigorates qi and blood circulation; analgesic — approximately 1.7× stronger than acetylsalicylic acid; anti-inflammatory — approximately 1.1× stronger than acetylsalicylic acid; inhibits pro-inflammatory mediators including nitric oxide and prostaglandin E2 in peritoneal macrophages; clinical studies: menstrual pain in 112 patients; migraine headache in 35 patients; different types of headache in 36 patients; general pain in 105 patients; caution with anticoagulants

— Hua Jiao (Pericarpium Zanthoxyli / Sichuan Pepper / Zanthoxylum): warms peripheral channels and collaterals; invigorates qi and blood circulation; anti-inflammatory — inhibits pro-inflammatory cytokines and suppresses vascular inflammatory process (TNF-α inhibition)

WESTERN THERAPEUTIC ACTIONS

* Muscle relaxant — Bai Shao + Zhi Gan Cao (smooth and skeletal muscles; leg cramps; hemodialysis cramps; restless leg syndrome; intestinal spasms; facial spasms; menstrual cramps)

* Analgesic — Bai Shao + Zhi Gan Cao (neuralgia, trigeminal neuralgia, neck pain, acute back pain, heel pain, lower back and leg pain, sciatica, gastric and abdominal pain, dysmenorrhea; enhanced by acupuncture); Dang Gui Wei (1.7× stronger than aspirin)

* Anti-inflammatory — Bai Shao (paeoniflorin, pro-inflammatory mediators↓, macrophage-like synoviocytes); Zhi Gan Cao (glucocorticoid enhancement); Dang Gui Wei (1.1× stronger than aspirin, NO↓, PGE2↓); Hua Jiao (TNF-α↓, vascular inflammation↓)

CHINESE THERAPEUTIC ACTIONS

* Tonifies Liver yin and Liver blood; nourishes and relaxes tendons and smooth muscles (Bai Shao, Zhi Gan Cao)

* Relieves spasms and cramps (Bai Shao, Zhi Gan Cao)

* Warms meridians; unblocks stagnation (Hua Jiao, Dang Gui Wei)

* Invigorates blood circulation (Dang Gui Wei, Hua Jiao)

DOSAGE

Standard: 3–4 capsules every 4–6 hours as needed. May increase to 5–6 capsules every 2–4 hours if necessary. For maximum effectiveness, take on an empty stomach with a tall glass of warm water.

Supplementary formulas: To enhance analgesic effect — add Herbal ANG. Neck and shoulder pain — add Neck & Shoulder (AC) or Neck & Shoulder (CR). Lower back pain — add Back Support (AC) or Back Support (CR). Arm pain (shoulder, elbow, wrist) — add Arm Support. Knee pain — add Knee & Ankle (AC) or Knee & Ankle (CR). Chronic musculoskeletal disorder with damaged soft tissues — add Flex (MLT). Arthritis with inflammation, swelling, redness, and pain — add Flex (Heat). Arthritic pain worsening in cold and rainy weather — add Flex (CD). Bone fractures, injuries, and bru