Concerning leg cramps, what has worked well for me over the years is flax seed oil.  When I first started doing seven to 10 day “juice fasts”, I would always get horrible leg cramps, typically in my hamstrings and occasionally my quads.  I commented about that to someone at a local vitamin store and was recommended to try taking flax seed oil.  I purchased a large bottle of 1,000 mg gel caps and started taking 4 each twice a day when doing the juice fast(s) and the leg cramps disappeared. 

After that, I started taking flax seed oil on a regular basis, mostly three to four 1,000 mg gel caps per day.  When the idea of doing a self-contained bicycle trip came along, I continued taking flax seed oil.   On my first few short trips of about 400 miles, I carried a large “bottle” of gel caps and took four or five in the morning before starting out and took five or six at the end of the day.  Not  only did I not have leg cramps, but my skin seemed to recover almost overnight from “sunburn”, even when using limited amounts of sunscreen.  Flax seed oil gel caps are somewhat heat tolerant, so, I made sure to pack the bottle deep inside my panniers to keep it cooler during the day.  If the bottle got warm, I would have to reach inside and break the gel caps apart, but that was typically after an eight or 10 hours on-the-road day.   On my most recent tour in 2019, I took five to six gel caps morning and evening and had no problems with leg cramps, either while training or doing actual loaded miles on the tour.

At the same time, I was taking a healthy dose of a calcium/magnesium blend. 

Additionally, as an aside, several years ago I read on a German language website that flax seed oil helps prevent the build-up of plaque inside the blood vessels and allegedly dissolves built up plaque if taken in sufficient quantity on a regular basis and helps maintain healthy cholesterol levels.  While undergoing cataract surgery, I was at the eye doctor’s office for a follow-up visit after the first surgery and one of the technicians was commenting to me that a couple of days previously, her doctor had done a blood screen to check her cholesterol levels, which were “out” according to the doctor, who then wanted to put her on medication.  She was not keen on that and told the doctor she was going to get a second opinion. 

I told her about what I had read on that German language website and suggested she purchase some 1,000 mg gel caps and start taking three or four twice a day for at least a couple of weeks before getting the second opinion, but not to say anything to the second doctor about taking the flax seed oil, lest he poo-poo such a thing.  At the same time, I suggested nothing-ventured-nothing-gained and at worst, she would be out the cost of the bottle of gel caps.  It was five or six weeks later that I saw her again when I had gone to the office for a check-up after the second cataract surgery.  I asked her if she had purchased some flax seed gel caps (yes) and asked her the result:  The second doctor asked her why she requested a cholesterol check, as everything was normal.

That is my two cents worth.  

Rich one thing to be cautious of with some magnesium supplements is B6 toxicity. 

It’s a well documented phenomenon. Too much vitamin B6, can cause really disabling nerve damage. Peripheral neuropathy, and that's a very miserable condition. There’s a very  long recovery time from this condition , if it's reversible at all. 

Some  preparations of magnesium are not pure magnesium, and they have vitamin B6. 

It’s not necessarily obvious, so you've got to look at the back of the packet or container. Pure magnesium is preferable.

this sounds weird, but pickle juice works. I asked a surgeon at Tacoma general hospital, who’s a cyclist too, about it. His answer? I use it regularly when I’m on a long trip. 

Another non drug thing I do is stretch my calves out fully before sleeping. Lie on the bed and grab your toes with your hand, slowly stretch out. You’ll feel it. I hold the stretch for 30 seconds. 

Rich, I'm glad your leg cramps have resolved. I've had them 4-5 times in my life and can't think of any worse pain. Even though yours are gone, for the benefit of others I thought I'd share this information about treatment from some medical journals I still have access to. They're all very reputable, and  are evidence-based so they include double blinded, placebo-controlled, randomized, and reproducible studies.

It's a bit long, tedious, and dry, but here's a summary of the information. If you're interested, there are references and some comments at the bottom:

The American Academy of Neurology recommends that non-pharmacologic strategies such as regular stretching of affected muscles before bedtime are commonly advised and may help reduce the frequency of nocturnal leg cramps, although high-quality evidence is limited. [1] These approaches are considered safe and should be first-line.

For pharmacologic treatment, the American Academy of Neurology states that quinine derivatives are likely effective (Level A) but should be avoided for routine use due to the risk of serious toxicity, including thrombocytopenia and arrhythmias. Quinine may be considered only in select patients after careful risk-benefit assessment.[1] Other agents with possible efficacy (Level C) include vitamin B complex, naftidrofuryl, and calcium channel blockers such as diltiazem, but the supporting evidence is limited to small studies and these agents are not universally available or approved for this indication in the United States. [1] Magnesium and vitamin E have not shown significant benefit in placebo-controlled trials. [1] 

Building on the guideline recommendations, recent clinical trials and systematic reviews provide further insight into both non-pharmacologic and pharmacologic strategies for nocturnal leg cramps.

Non-pharmacologic interventions, particularly stretching, have some evidence for reducing cramp severity, though the effect on frequency is less certain. A Cochrane review found that daily calf and hamstring stretching over six weeks may reduce cramp pain severity in older adults, but the impact on cramp frequency is inconsistent and the certainty of evidence is low. [2]  Patient-reported data also support massage, stretching, and walking as helpful, low-risk options, with many patients finding these approaches at least somewhat beneficial. [3]

Pharmacologic therapies remain controversial due to limited efficacy and safety concerns. Magnesium supplementation, despite widespread use, has not demonstrated clinically meaningful benefit for idiopathic nocturnal leg cramps in older adults according to multiple randomized trials and meta-analyses.[4-5] However, a recent trial of magnesium oxide monohydrate showed a modest reduction in cramp frequency and duration compared to placebo, suggesting possible benefit with specific formulations, though further validation is needed.[6] For other agents, a recent randomized trial found that vitamin K2 significantly reduced the frequency, severity, and duration of nocturnal leg cramps, with a favorable safety profile, representing a promising new option. [7]

Muscle relaxants such as baclofen, orphenadrine, carisoprodol, and methocarbamol have shown efficacy in reducing cramp frequency and severity in select populations, but adverse effects are common and these agents are not routinely recommended for idiopathic nocturnal leg cramps.[8] Over-the-counter analgesics are frequently used by patients, but their effectiveness is limited and they carry potential risks, especially with chronic use.[3]

In summary, stretching and other non-pharmacologic measures remain first-line due to safety and modest benefit, while vitamin K2 and certain muscle relaxants may offer additional options for refractory cases, though further research and individualized risk assessment are warranted. Magnesium and other supplements generally lack robust evidence for efficacy in idiopathic nocturnal leg cramps.

1. Assessment: Symptomatic Treatment for Muscle Cramps (An Evidence-Based Review): Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.
Katzberg HD, Khan AH, So YT. Neurology. 2010;74(8):691-6.
2. Non-Drug Therapies for the Secondary Prevention of Lower Limb Muscle Cramps.
Hawke F, Sadler SG, Katzberg HD, et al.
The Cochrane Database of Systematic Reviews. 2021;5:CD008496.
3. Patient-Reported Leg Cramp Treatments and Their Effectiveness.
Khandalavala B, Geske J, Karloff M.
Journal of the American Board of Family Medicine : JABFM. 2024 Nov-Dec;37(6):1123-1129.  
4. Magnesium for Skeletal Muscle Cramps.
Garrison SR, Korownyk CS, Kolber MR, et al.
The Cochrane Database of Systematic Reviews. 2020;9:CD009402. 
5. Effect of Magnesium Oxide Supplementation on Nocturnal Leg Cramps: A Randomized Clinical Trial.
Roguin Maor N, Alperin M, Shturman E, et al.
JAMA Internal Medicine. 2017;177(5):617-623. 
6. A Randomized, Double-Blind, Placebo-Controlled, Multicenter Study Assessing the Efficacy of Magnesium Oxide Monohydrate in the Treatment of Nocturnal Leg Cramps.
Barna O, Lohoida P, Holovchenko Y, et al.
Nutrition Journal. 2021;20(1):90. 
7. Vitamin K2 in Managing Nocturnal Leg Cramps: A Randomized Clinical Trial.
Tan J, Zhu R, Li Y, et al.
JAMA Internal Medicine. 2024; 184(12):1443-1447.  
8. Long-Term Use of Muscle Relaxant Medications for Chronic Pain: A Systematic Review.
Oldfield BJ, Gleeson B, Morford KL, et al.
JAMA Network Open. 2024;7(9):e2434835.  

*thrombocytopenia - not enough platelets, one of the substances in our blood that helps us clot when we need to stop bleeding
* efficacy - producing the desired results
* idiopathic - something whose cause we don't know

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A few comments I'd like to add:
+ When you do stretching exercises, you need to hold the position for at least 60 seconds, and preferably a couple of minutes, to get any real benefit. And you need to do a minimum of 4-5 repetitions. Stretching correctly might be enough by itself without any medications.
+ This is anecdotal, so I hate to add it, but it's worked for a number of my patients:  make sure the sheets/blankets at the foot of the bed are untucked. When your legs are restricted it can cause spasms.
+ Natto, a Japanese food made from fermented soybeans, appears to have a ridiculous amount of vitamin K2 (see article above). If the stretching alone doesn't work, it might be better than an expensive pill.